The present invention relates to disposable hygiene products and more specifically, to methods and apparatuses for processing disposable hygiene products. More specifically, the invention relates to cutting and applying segments of one web to attach to a disposable diaper. Various types of automatic manufacturing equipment have been developed which produce the desired results with a variety of materials and configurations.
When manufacturing hygiene products, such as baby diapers, adult diapers, disposable undergarments, incontinence devices, sanitary napkins and the like, a common method of applying discrete pieces of one web to another is by use of a slip-and-cut applicator. A slip-and-cut applicator is typically comprised of a cylindrical rotating vacuum anvil, a rotating knife roll, and a transfer device. In typical applications, an incoming web is fed at a relatively low speed along the vacuum face of the rotating anvil, which is moving at a relatively higher surface speed and upon which the incoming web is allowed to “slip”. A knife-edge, mounted on the rotating knife roll, cuts a off a segment of the incoming web against the anvil face. This knife-edge is preferably moving at a surface velocity similar to that of the anvil's surface. Once cut, the web segment is held by vacuum drawn through holes on the anvil's face as it is carried at the anvil's speed downstream to the transfer point where the web segment is transferred to the traveling web.
Typical vacuum rolls used in the prior art have rows of vacuum holes which are fed by cross-drilled ports, each being exposed to the source of vacuum by commutations, as the ports move into a zone of negative pressure in a stationary manifold. Such a configuration serves to apply vacuum sequentially to each successive row of holes.
Current knife or die designs can wear over time. It has been discovered that one source of dulling is corrosion. It would be desirable to avoid dulling through corrosion.